In liquid crystal display devices, for example, in some mobile phones, it is required to provide a backlight module as a light source for a display screen. The backlight module generally includes an LED lamp strip to generate a backlight, and includes a light guide plate and optical sheets to uniform backlight brightness.
For an irregular backlight module having a notch at a corner, the light received by edges of the notch region from a light source is uneven, which results in the uneven brightness at the display edges. In the conventional technology, in order to ensure the even brightness of the notch region, an auxiliary light source is generally provided at the notch, and the brightness of the main light source and the auxiliary light source are controlled by a main board, so as to display contents in the corresponding regions. In this case, considering the placement and the wiring of the auxiliary light source at the notch, it is required to provide a light shielding region in addition to shield the auxiliary light source and related control circuit at the notch, which results in a smaller display region at the notch, a larger size of the notch, and a quite wider frame. Further, it is required to separately provide a control circuit for the auxiliary light source, which results in a complicated main board circuit of the display device and thus an increased cost.